THE GIST

- Horses remain loyal to humans with which they have had past, positive encounters.

- The animals remember people even after long separation.

- Horses understand vocal commands better than expected.

Human friends may come and go, but a horse could be one of your most loyal, long-term buddies if you treat it right, suggests a new study.

Horses also understand words better than expected, according to the research, and possess "excellent memories," allowing horses to not only recall their human friends after periods of separation, but also to remember complex, problem-solving strategies for ten years or more.

The bond with humans likely is an extension of horse behavior in the wild, since horses value their own horse relatives and friends, and are also open to new, non-threatening acquaintances.

"Horses maintain long-term bonds with several members of their family group, but they also interact temporarily with members of other groups when forming herds," explained Carol Sankey, who led the research, and her team.

"Equid social relationships are long-lasting and, in some cases, lifelong," added the scientists, whose paper has been accepted for publication in the journal Animal Behavior.

Ethologist Sankey of the University of Rennes and her colleagues studied 20 Anglo-Arabian and three French Saddlebred horses stabled in Chamberet, France. The scientists tested how well the horses remembered a female trainer and her instructions after she and the horses had been separated up to eight months.

The training program for the horses consisted of 41 steps associated with basic grooming and medical care. For example, the horses had to remain immobile in response to the verbal command "reste!" which is French for "stay." The horses also had to lift their feet, tolerate a thermometer inserted into the rectum and more. When a horse did as it was instructed, the trainer rewarded it with food pellets.

With tasty rewards, the horses "displayed more 'positive' behaviors toward the experimenter, such as sniffing and licking," the researchers wrote. Horses do this as a sign of affiliation with each other, so they weren't necessarily just seeking more food.

The scientists added, "Horses trained without reinforcement expressed four to six times more 'negative' behaviors, such as biting, kicking and 'falling down' on the experimenter."